They pre-empted the window seats in the meeting room by booking early.

pre-empted 是动词 pre-empt 的过去式形式。pre-empt 由前缀 pre-（表示"提前"）和动词 empt（来自拉丁语 emere，意为"取得"）组成，意思是"抢先取得"或"预先阻止"。pre-empted 在这里表示"通过提前行动来确保获得（座位）"。